LG 32LH20 Service Manual

The LG 32LH20 is a 32-inch LCD HDTV featuring 720p resolution, built-in ATSC/NTSC tuner, multiple HDMI inputs, component video inputs, USB connectivity, Intelligent Sensor technology for automatic picture optimization, and LG's proprietary picture enhancement technologies. This service manual provides comprehensive technical information for qualified service technicians including disassembly procedures, circuit diagrams, troubleshooting guides, and replacement part information.

1. Safety Precautions 2. Product Specifications 3. Disassembly Procedures 4. Circuit Diagrams 5. PCB Layouts 6. Troubleshooting Flowcharts 7. Voltage Measurements 8. Replacement Parts List 9. Adjustment Procedures 10. Firmware Update 11. Service Mode Access

Safety Precautions

Before servicing the LG 32LH20, observe all safety precautions to prevent injury and equipment damage.

Warning	Precaution
High Voltage	Discharge capacitors before servicing power supply
ESD Protection	Use anti-static wrist strap when handling PCBs
Lifting Safety	Two-person lift required for panel replacement
Laser Safety	Avoid direct eye exposure to backlight LEDs
Heat Protection	Allow unit to cool before disassembly

Product Specifications

Model: 32LH20
Screen Size: 32 inches LCD
Resolution: 1366 x 768 (720p)
Tuner: ATSC/NTSC/QAM
Inputs: 3x HDMI, 2x Component, 2x Composite, 1x PC Input, 1x USB
Power Supply: 120V AC, 60Hz, 150W max
Backlight: CCFL
Main Board: EAX43553801
Power Board: EAY40422801
T-Con Board: 6870C-0284A

Disassembly Procedures

Step-by-step instructions for safe disassembly of the LG 32LH20.

Remove stand: Lay TV face down on soft surface, remove 4 screws securing stand.
Remove rear cover: Remove all visible screws from rear casing.
Separate front bezel: Carefully pry plastic clips around perimeter.
Access main boards: Remove metal shield covering PCBs.
Disconnect cables: Note cable positions before disconnecting.

WARNING! Handle LCD panel with extreme care to avoid cracking.

Circuit Diagrams

Complete schematic diagrams for all major circuits.

Diagram	Description
Power Supply	Primary and secondary power circuits
Main Board	Signal processing and control circuits
Inverter Board	Backlight driver circuits
T-Con Board	Timing controller and LVDS circuits
Audio Board	Amplifier and speaker circuits

PCB Layouts

Physical board layouts with component identification.

Main Board EAX43553801: Component locations and test points
Power Board EAY40422801: Voltage regulator circuits
T-Con Board 6870C-0284A: LVDS connector pinouts
Inverter Board: Transformer and capacitor locations
Button Board: Front control panel layout

Troubleshooting Flowcharts

Systematic diagnostic procedures for common failures.

Symptom	Diagnostic Path
No Power	Check AC input → Fuse → Standby voltage → Main power
No Backlight	Check inverter input → Backlight on signal → Inverter output
No Video	Check input signal → Main board processing → T-Con output
No Audio	Check audio input → Main board processing → Audio amplifier
No Tuner	Check antenna input → Tuner power → Tuner I2C communication

Voltage Measurements

Critical voltage test points and expected values.

Test Point	Expected Voltage	Tolerance
Standby 5V	5.1V DC	±5%
Main 12V	12.0V DC	±5%
Main 24V	24.0V DC	±5%
Panel VCC	12.0V DC	±5%
AVDD	15.0V DC	±5%
VGH	25.0V DC	±10%
VGL	-6.0V DC	±10%

Replacement Parts List

Authorized replacement components with part numbers.

Main Board: EAX43553801/EAX43553802
Power Supply Board: EAY40422801
T-Con Board: 6870C-0284A
LCD Panel: LC320WXE-SBB1
Inverter Transformer: 6871L-0894A
Main Filter Capacitor: 450V 120μF
Backlight CCFL: 32" CCFL Tube Set
Remote Control: AKB72915207

Adjustment Procedures

Factory adjustment and calibration procedures.

White Balance: Access service menu, adjust R/G/B gain and offset
Geometry: Adjust horizontal/vertical position and size
Color Temperature: Calibrate to 6500K standard
Backlight Level: Set to factory specification
Audio Levels: Balance left/right channels

NOTE: All adjustments require proper test equipment.

Firmware Update

Procedures for updating TV firmware.

Download latest firmware from LG service website
Format USB drive to FAT32
Copy firmware file to root directory
Insert USB while TV is off
Power on TV - update should begin automatically
Do not interrupt power during update

WARNING! Incorrect firmware can permanently damage TV.

Service Mode Access

Methods for entering service and factory modes.

Mode	Access Method	Purpose
Service Menu	Menu + 0000 on remote	Adjustment and calibration
Factory Mode	Vol- + Menu on TV buttons	Factory reset and tests
In-Service Mode	Menu + 0413	Extended service functions
Burn-in Prevention	Service menu option	Pixel shifting and orbiter

CAUTION! Service mode changes can affect TV operation.